This invention relates to a power feeding apparatus for a slidable structural body in which a wire harness is installed by the use of a pivotal link arm in order to continuously feed power to the slidable structural body such as a slide door of an automobile from a fixed structural body such as a vehicle body.
FIG. 13 shows a first form of a conventional power feeding apparatus for a slidable structural body (see Patent Literature 1).
This power feeding apparatus 51 includes a guide rail 53 provided horizontally on a slide door 52 of an automobile, a slider 54 slidably engaged with the guide rail 53, and a pair of openable/closable links 55, 56 of a generally mountain-shape connected at one end to the slider 54 and connected at the other end to the guide rail 54.
A wire harness 57 is installed to extend, while being bent into a generally U-shape, from the link 55 via the slider 54 to a vehicle body (58)—side fixing portion 59, and one end of the wire harness 57 is connector connected to a slide door-side wire harness 60, and the other end is connector connected to a vehicle body-side wire harness 61.
The pair of links 55, 56 are opened and closed (expanded and contracted) in accordance with the opening and closing of the slide door 52, and the slider 54 moves along the guide rail 53 relative thereto, and is always located in the vicinity of the vehicle body-side fixing portion 59.
FIG. 14 shows a second form of a conventional power feeding apparatus for a slidable structural body (see Patent Literature 2).
This power feeding apparatus 62 is constructed such that three links 65 of different lengths are swingably connected together in a horizontal direction between a slide door 63 of an automobile and a vehicle body 64, and a wire harness 65 is installed to extend from the vehicle body 64 to the slide door 63 along each link 65.
In accordance with the opening and closing of the slide door 63, each link 65 is pivotally moved in an opposite direction to absorb the amount of movement of the slide door 63.
FIG. 15 to FIG. 17 show a third form of a conventional power feeding apparatus for a slidable structural body (see Patent Literature 3).
This power feeding apparatus 67 includes a synthetic resin-made protector (case) 32 mounted on a slide door 68 of an automobile, and a metallic leaf spring 70 which is fixed at one end within the protector and supports and urges a wire harness 69 upwardly at the other end. The protector 32 is formed by a base 32a and a cover 32b (FIG. 17).
The wire harness 69 is installed to extend to the slide door from an opening 71 at a front end of the protector 32, and is installed to extend from an elongated opening 72 at a lower end of the protector 32 via an intervening space 73 to a harness fixing member 12 (FIG. 17) disposed in the vicinity of a vehicle body (74)—side step, and is connected from the harness fixing member 12 to a wire harness (not shown).
The wire harness 69 includes a plurality of insulating sheathed wires and a bendable corrugated tube made of a synthetic resin. The corrugated tube has an oval cross-section (flattened type), and is installed between the protector 32 and the harness fixing member 12, with its longer diameter portion disposed vertically.
When the slide door 68 of FIG. 15 is fully closed, the wire harness 69, while bending the leaf spring 70 downward, is pulled rearward, with the harness fixing member 12 serving as a support point, and when the slide door 68 is fully opened (FIG. 16 shows a condition immediately before the fully-opened condition), the wire harness 69, while bending the leaf spring 70 downward, is pulled forward, with the harness fixing member 12 serving as the support point, and when the slide door 68 is half opened, the wire harness 69 tends to hang down as indicated in chain lines of FIG. 14, but is urged upward by the leaf spring 70, so that its surplus length is absorbed, and the hanging-down and the catching of the wire harness 69 resulting therefrom at the time of closing the door are prevented.                [Patent Literature 1] JP-A-2001-122054 (FIG. 1)        [Patent Literature 2] JP-A-2001-151042        [Patent Literature 3] JP-A-2002-17032 (FIGS. 4 to 5)        
However, in the above first power feeding apparatus 51 of FIG. 13, there has been a problem that the number of the parts and the weight are increased by the long guide rail 53 and the links 55, 56, and when the links 55, 56 are expanded and contracted (opened and closed), the wire harness 57 is bent with a small radius between the slider 54 and the link 55, so that a large bending stress acts on the wire harness 57, and therefore there has been a fear that the durability of the wire harness 57 and the operability of the slide door 52 are lowered.
Also, in the above second power feeding apparatus 62 of FIG. 14, the wire harness 66 is bent in a complicated manner in accordance with the pivotal movement of each link 65, and therefore there has been a fear that the durability of the wire harness 66 is lowered. There has been a fear that the wire harness 66 is bent with a small radius particularly between the link 65 and the slide door 63 and between the link 65 and the vehicle body 64, so that a large bending stress acts on the wire harness 66.
Furthermore, in the above third power feeding apparatus 67 of FIG. 15, a surplus length of the wire harness 69 is absorbed (received) into the protector 32, and therefore there has been a problem that the protector 32 is large in size, and occupies a large area inside the slide door 68, so that the degree of freedom of arrangement of other auxiliary equipments, etc., is limited. And besides, the wire harness 69 is received in a bent manner within the protector, and therefore there has been a problem that the long wire harness 69 is needed (the corrugated tube and a wire portion become long), so that the high cost and the increased weight are encountered.
These fears can arise similarly even in the case where for example, each power feeding apparatus is applied not only to the slide door of the automobile but also to a slidable structural body such as a slide door of a train, etc., and a slide door of a producing apparatus, a detecting apparatus, etc. In this case, a vehicle body, an apparatus body, etc., are generically called a fixed structural body.